1. Field of the Invention
The invention relates to consumer electronic devices and more particularly, methods and apparatus associated with the design of displays for thin-profile consumer electronic devices.
2. Description of the Related Art
From a visual stand point, users often find compact and sleek designs of consumer electronic devices more aesthetically appealing. As an example, portable electronic device designs that are both thin and light-weight are often popular with consumers. In some thin device designs, one face of the device is almost entirely dedicated to a viewable portion of the display while other input/output components are arranged around the sides and/or back of the device opposite the display. Typically, the display is surrounded by a thin profile enclosure where the display controller, main logic board, battery and other interface circuitry are all packaged within the enclosure.
Often back-lit displays are used in thin-profile electronic devices. A back-lit display, such as a liquid crystal display, can consist of a display glass component with a number of elements that can be controlled to vary the light transmissivity across the display glass. By varying the light transmissivity across the display glass, different images can be viewed on the back-lit display.
One objective in the design of back-lit displays is to provide relatively homogenous optical properties, such as an even lighting brightness, across the display from the edges to the center. For example, it is undesirable for the back lighting to generate local areas of brightness and dimness on the display, such as dimmer near the edges and brighter near the center. Local areas of brightness and dimness on the display are undesirable because the contrast level of the image output from the display is altered. The alteration of the contrast level of the image can cause details of the image that are viewable on a display with a more homogenous brightness to become un-viewable.
The distribution of the lighting brightness across a display can be affected by the placement of one or more illumination sources that generate the light emitted from the display and a path that the light from the illumination sources travels before it is emitted from the display. As an example, a light pipe can be used to distribute light from the illumination sources near the edge of the display to different parts of the display including the opposite edge of the display. The path that light takes before it is emitted from the display can include reflecting off of one or more different surfaces. Unless the surfaces are properly designed, light reflection can cause local areas of brightness and dimness on the display and subsequently distort the displayed images.
As consumer electronic devices and their associated display stacks are made thinner, bending of the device including the display stack becomes an issue that can affect the light emitting properties of the display. For example, the force of a user interacting with an electronic device, such as via a touch screen interface, can cause a light pipe and an associated display glass in the display underneath the touch screen to move and/or deform. The resulting movement and deformation of the light pipe can change the light paths associated with the light pipe such that its light emitting properties are altered. As the light pipe is flexed from one shape to another shape, the light emitting properties of the light pipe can be altered such that a noticeable distortion in an image output on the display is generated.
In view of the above, display components, such as light pipe and its supporting structure, are desired that address optical issues that can result from the structural deformation associated with operating a light-weight portable electronic device with a thin and compact enclosure.